Abstract

Precious metal oxides of IrO2 were prepared by thermal treatment of the macromolecular Chitosan center dot(IrCl3)(x) and PSP-4-PVP center dot(IrCl3)(x) precursors. Using this procedure, pure IrO2, phases were formed. The nature of the polymeric precursor is acting as a solid state template and influences the size of the iridium dioxide but not significantly the morphology, and the obtained IrO2 nanoparticles are about 15 nm. For the first time, the photocatalytic degradation of methylene blue using IrO2 was measured founding a moderated activity. The inclusion of IrO2 into SiO2 was performed using a combined solution of the Chitosan and PVP precursors by the solgel method. Subsequent pyrolysis of the isolated solid-state Chitosan center dot(IrCl3)(x)(SiO2)(y) and PSP-4-PVP center dot(IrCl3)(x)(SiO2)(y) give rise to the IrO2//SiO2 nanocomposites. The IrO2 particles are distributed uniformly inside the matrix of SiO2 leading to stable semi porous materials appropriate for high temperature catalytic applications. The IrO2 nanoparticles formed from the PVP precursor are mainly nanobars of 10 nm width, while that for the chitosan precursor are around 25 nm. The IrO2/SiO2 composites exhibit a moderate photocatalytic activity toward the degradation of methylene blue and similar to that of IrO2.